Changes
added --save
6. For each VE, create ethN devices (ignore warnings about "Container does not have configured veth") on the host:
/usr/sbin/vzctl set 100 --netif_add eth0--save /usr/sbin/vzctl set 100 --netif_add eth1--save
The above creates corresponding veth100.0 and veth100.1 devices on the host and updates the host /etc/vz/conf/100.conf file with generated MAC addresses for the veth devices.